Spatial light modulators, such as micromirror-based spatial light modulators, liquid crystal panels and liquid-crystal-on-silicon panels, have been widely used in display systems. In display systems employing spatial light modulators, apertures, such as light blocking/absorbing masks, are often provided to cover non-active areas of the spatial light modulators and to block image artificial effects caused by unavoidable illumination of surrounding areas, such as bond wires, bond pads, die edges, test structures etc, from being visible in projected images. Utilization of apertures in spatial light modulators may significantly increase costs of spatial light modulators.
In a typical display system employing a spatial light modulator, the modulator comprises a package in which the array of individually addressable pixels is enclosed for protection. Illumination light of the display system is often focused on the active area of the spatial light modulator, wherein the active area is referred to an area in which pixels of the spatial light modulator are modulated for generating desired images. The size of the aperture used with the spatial light modulator is substantially determined so as not to block the incident light from illuminating the active area. Once the size of the aperture is determined, the size of the die (e.g. the substrate on which functional members of the spatial light modulator are formed) of the spatial light modulator is determined based on the aperture size so as to avoid imaging surrounding areas of the spatial light modulator on to produced images. As the distance between the aperture and the die (or the active area) increases, the size of the die increases, which increases the cost of the spatial light modulator.
The aperture used with the spatial light modulator itself may account for a large percentage of the total cost of the spatial light modulator because a typical aperture comprises relatively expensive multi-layer dichroic coatings. The multi-layered dichroic coatings each often comprise exotic materials that are often expensive. Moreover, the apertures are often formed on top or bottom surfaces of the package lids of packages, in which pixel arrays of the spatial light modulators are enclosed for protection. Forming the apertures on the package lids by coating the exotic materials is costly and difficult.